Gear pumps often include a housing or plate that holds a set of intermeshing gears. As the gears turn, fluid moves between the gear teeth and the housing and is expelled out the pump due to the intermeshing of the gears. The gears are attached to shafts that run axially from the gear faces, and these shafts run on one or more bearing surfaces.
As will be appreciated, during operation it is desirable to seal the housing and plate components, including shaft sealing components, in a manner that prevents process fluid from leaking out of the pump. Often o-rings, gaskets or other sealants are disposed between the opposing sealing surfaces to prevent such leakage. In other cases sealing is achieved between a pair of opposing metal surfaces that are formed to be extremely flat and parallel and very smooth (i.e., they have a fine surface finish).
When using o-rings and gaskets, issues can arise when the operating temperature of the pump exceeds the maximum temperature of the sealing component or where the o-ring material is incompatible with the fluid being pumped (e.g., where the pumped fluid is corrosive or otherwise harsh). This can cause the sealing component to degrade or disintegrate, thereby affecting its ability to seal. When using metal-to-metal face seals, the two mating faces will not produce an effective seal at high pressure or low viscosity unless the surface finish of the opposing surfaces is very fine. The opposing surfaces must also be very flat and parallel. If a rough surface finish is used, or if the surfaces are not sufficiently flat and parallel, the joint will leak.
Thus, there is a need for a high temperature face sealing arrangement that eliminates the need for an o-ring, gasket or other secondary sealing component, and which can be used to effectively seal joints at high temperatures and pressures.